This invention relates to fuel injectors in general, and more particularly to a high-pressure direct injection fuel injector assembly which includes a modified seat for enhanced compressed natural gas jet mixing for maximizing fuel combustion.
In the case of internal combustion engines having direct injection systems, fuel injectors are conventionally used to provide a precise amount of fuel needed for combustion. Compressed natural gas (hereinafter sometimes referred to as xe2x80x9cCNGxe2x80x9d) is a common automotive fuel for commercial fleet vehicles and residential customers. In vehicles, the CNG is delivered to the engine in precise amounts through fuel injectors, hereinafter referred to as xe2x80x9cCNG injectorsxe2x80x9d, or simply xe2x80x9cfuel injectorsxe2x80x9d. Injectors of the type contemplated herein are described in commonly assigned U.S. Pat. No. 5,494,224, the disclosure of which is incorporated by reference herein. The fuel injector described above is required to deliver the precise amount of fuel per injection pulse and maintain this accuracy over the life of the injector. In order to optimize the combustion of fuel, certain strategies are required in the design of high-pressure fuel injectors. These strategies are keyed to the delivery of fuel into the intake manifold of the internal combustion engine in precise amounts and flow patterns. Conventional fuel injector designs have failed to optimize the combustion of fuel injected into the intake manifold of an internal combustion engine.
The present invention overcomes the disadvantages of conventional fuel injectors and provides a fuel injector which incorporates a needle with a novel seat design, which can provide various flow patterns and improved spray atomization for fuel for improved combustion.
The present invention provides a fuel injector having a fuel inlet, a fuel outlet, and a fuel passageway extending from the fuel inlet to the fuel outlet along a longitudinal axis. The fuel injector includes a body, a needle slidingly disposed within the body and a seat disposed at the fuel outlet. The seat has a plurality of passages, each of the plurality of passages having a central axis having an angle of inclination relative to the longitudinal axis.
The present invention also provides a spray pattern generated by a fuel injector having a fuel inlet, a fuel outlet, a fuel passageway extending from the fuel inlet to the fuel outlet along a longitudinal axis, a body, a needle slidingly disposed within the body, and a seat disposed at the fuel outlet. The seat has a plurality of passages, each of the plurality of passages having a central axis having an angle of inclination relative to the longitudinal axis. The spray pattern includes a fan shape and at least one plume adjacent the fan shape.
The present invention also provides a method of generating a spray pattern from a fuel injector in a direct injection application. The fuel injector has a body, a longitudinal axis, a needle slidingly disposed within the body, and a seat disposed at the fuel outlet. The method includes the steps of providing the seat with a plurality of passages, each of the plurality of passages having a central axis having an angle of inclination relative to the longitudinal axis, and supplying fuel to the fuel injector so that a spray pattern is formed.